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1.
Chem Commun (Camb) ; 58(43): 6280-6283, 2022 May 26.
Artigo em Inglês | MEDLINE | ID: mdl-35507823

RESUMO

We describe here a facile synthesis of 9-arylfluorenes and spirobifluorenes from readily available 1,1-diarylmethylamines and iodoarenes through Pd-cataylsed C(sp2)-H arylation and a sequential deaminative annulation. The reaction features high efficiency and simplicity of operation, constituting an interesting shortcut to access fluorene compounds.


Assuntos
Catálise
2.
Org Biomol Chem ; 20(20): 4091-4095, 2022 05 26.
Artigo em Inglês | MEDLINE | ID: mdl-35522070

RESUMO

We describe here a Ni-catalysed deamidative fluorination of diverse amides with electrophilic fluorinating reagents. Different types of amides including aromatic amides and olefinic amides were well compatible, affording the corresponding acyl fluorides in good to excellent yields.


Assuntos
Amidas , Halogenação , Catálise , Fluoretos , Indicadores e Reagentes
3.
Chem Commun (Camb) ; 58(46): 6653-6656, 2022 Jun 08.
Artigo em Inglês | MEDLINE | ID: mdl-35593224

RESUMO

A Cu-catalyzed asymmetric 1,6-conjugate addition of in situ generated para-quinone methides (p-QMs) with ß-ketoester has been developed to construct a ketoester skeleton bearing an adjacent tertiary-quaternary carbon stereocenter in good yields and high enantioselectivities. This is the first example of metal-catalyzed asymmetric transformations of the in situ generated p-QMs, avoiding using pre-synthesized p-QMs requiring bulky 2,6-substitutions and highlighting a new dual catalytic activation with the chiral bis(oxazoline)-metal complex acting as a normal Lewis acid to activate the ß-ketoesters and a source of Brønsted acid responsible for generating the p-QMs in situ.


Assuntos
Cobre , Indolquinonas , Catálise , Metais
4.
Org Lett ; 23(17): 6750-6755, 2021 Sep 03.
Artigo em Inglês | MEDLINE | ID: mdl-34406770

RESUMO

The catalytic diastereo- and enantioselective syntheses of C2-symmetric axially chiral 1,4-dicarbonyl derivatives with 2,3-quaternary stereocenters were achieved by utilizing an organo-/iodine binary catalytic strategy. The reactions proceeded well under mild conditions without metals or strong bases.

5.
Chem Commun (Camb) ; 57(65): 8055-8058, 2021 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-34291778

RESUMO

An efficient Pd-catalysed ß-C(sp3)-H arylation of diverse native amides with aryl iodides was developed. This protocol overcomes the necessity of the Thorpe-Ingold effect and features broad substrate scope and good functional group tolerance. The potential application of this protocol is collectively demonstrated by gram-scale synthesis and the synthesis of several bioactive molecules.

6.
Chem Commun (Camb) ; 57(52): 6424-6427, 2021 Jun 29.
Artigo em Inglês | MEDLINE | ID: mdl-34095920

RESUMO

A new and efficient strategy for ring-opening reactions of nitrocyclopropanes is developed for the first time for the divergent synthesis of enynes and enesters via in situ generated highly reactive electron-deficient intermediate allenes. Controllable approaches resulted in enynes and enesters with up to 89% and 90% yields, respectively. The reaction features easy operation, involves green solvents and simple inorganic bases, and is transition-metal free.

7.
Chem Commun (Camb) ; 57(37): 4544-4547, 2021 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-33956008

RESUMO

The Pd-cataylsed direct ortho-C(sp2)-H fluorination of aromatic ketones has been developed for the first time. The reaction features good regioselectivity and simple operations, constituting an alternative shortcut to access fluorinated ketones. A concise synthesis of anacetrapib has also been achieved by using late-stage C-H fluorination as a key step.


Assuntos
Cetonas/química , Oxazolidinonas/síntese química , Paládio/química , Catálise , Halogenação , Estrutura Molecular , Oxazolidinonas/química
8.
Org Biomol Chem ; 19(20): 4478-4482, 2021 05 26.
Artigo em Inglês | MEDLINE | ID: mdl-33950054

RESUMO

An efficient ruthenium-catalyzed method has been developed for the direct N-alkylation of sulfur-containing amines with alcohols, for the first time, by a step-economical and environmentally friendly hydrogen borrowing strategy. The present methodology features base-free conditions and broad substrate scope, with water being the only by-product. Moreover, this protocol has been applied to the synthesis of the pharmaceutical drug Quetiapine.

9.
Org Biomol Chem ; 19(30): 6588-6592, 2021 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-34023869

RESUMO

Using visible light as a driving force and molecular oxygen as a green oxidant, we developed bis(oxazoline)-Ni(acac)2 catalyzed asymmetric α-hydroxylation of ß-keto esters under low photosensitizer loading, and the protocol enabled an efficient transformation to provide the desired chiral α-hydroxy-ß-keto esters in high yields (up to 99%) and enantioselectivities (up to 99% ee) at room temperature.

10.
Org Lett ; 23(7): 2471-2476, 2021 Apr 02.
Artigo em Inglês | MEDLINE | ID: mdl-33733793

RESUMO

A sequential enantioselective conjugate addition/hydroalkoxylation between in situ generated ortho-quinomethanes and ynones by combining bifunctional squaramide and DBU catalysis has been developed. A variety of eight-membered cyclic ethers with two contiguous tertiary stereocenters were obtained in high yields with excellent stereoselectivities. This reaction not only provides a new strategy for constructing enantioenriched eight-membered cyclic ethers but also demonstrates the practicability of ynones as C4-syntons for the synthesis of chiral medium-membered rings.

11.
Chem Commun (Camb) ; 57(6): 765-768, 2021 Jan 26.
Artigo em Inglês | MEDLINE | ID: mdl-33355557

RESUMO

Herein, we report a novel strategy to access CH2F-containing ketones through Pd-catalysed ß-selective methyl C(sp3)-H fluorination. The reaction features high regioselectivity and a broad substrate scope, constituting a modular method for the late-stage transformation of the native methyl (CH3) into the monofluoromethyl (CH2F) group.

12.
Org Lett ; 22(21): 8250-8255, 2020 Nov 06.
Artigo em Inglês | MEDLINE | ID: mdl-33075228

RESUMO

Herein we report a novel Cu-catalyzed regioselective C2-H alkylation of benzimidazoles with aromatic alkenes. The reaction features exclusive regioselectivity and broad substrate scope in the intermolecular alkylation of benzimidazoles with terminal and internal aromatic alkenes, constituting a modular access toward benzimidazole-containing 1,1-di(hetero)aryl alkanes. The intramolecular C2-H alkylation of benzimidazoles with aromatic alkenes has been achieved in an endo-selective manner. The enantioselective C2 alkylation of benzimidazoles has also been realized with moderate to good stereocontrol.

13.
Org Biomol Chem ; 18(34): 6732-6737, 2020 09 14.
Artigo em Inglês | MEDLINE | ID: mdl-32832956

RESUMO

A nitrate-promoted Pd-catalysed mild cross-dehydrogenative C(sp2)-H bond oxidation of oximes or azobenzenes with diverse carboxylic acids has been developed. In contrast to the previous catalytic systems, this protocol features mild conditions (close to room temperature for most cases) and a broad substrate scope (up to 64 examples), thus constituting a versatile method to directly prepare diverse O-aryl esters. Moreover, the superiority of the nitrate additive in this mild transformation was further determined by experimental and computational evidence.

14.
J Org Chem ; 85(15): 9491-9502, 2020 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-32692168

RESUMO

The functionalization of indoles in the carbocyclic ring has been achieved via organocatalytic enantioselective Friedel-Crafts benzhydrylation of hydroxyindoles with in situ generated ortho-quinomethanes in oil-water biphases, allowing an efficient access to varied diarylindolylmethanes with a wide substrate scope. The high yields, excellent stereoselectivities, mild conditions, low catalyst loading, and easy scalability also demonstrated the interest of this novel methodology.

15.
Org Biomol Chem ; 18(26): 4927-4931, 2020 07 08.
Artigo em Inglês | MEDLINE | ID: mdl-32573633

RESUMO

A highly enantioselective homogeneous fluorination of cyclic ß-keto esters catalyzed by diphenylamine linked bis(oxazoline)-Cu(OTf)2 complexes has been established in a continuous flow microreactor. The microreactor allowed an efficient transformation with reaction times ranging from 0.5 to 20 min, and the desired products were afforded in high yields (up to 99%) with excellent enantioselectivities (up to 99% ee) at a low catalyst loading of 1 mol%.

16.
Org Lett ; 22(6): 2396-2402, 2020 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-32124610

RESUMO

Selective C(sp3)-C(sp2) bond construction is of central interest in chemical synthesis. Despite the success of classic cross-coupling reactions, the cross-dehydrogenative coupling between inert C(sp3)-H and C(sp2)-H bonds represents an attractive alternative toward new C(sp3)-C(sp2) bonds. Herein, we establish a selective inter- and intramolecular C(sp3)-H arylation of alcohols with nondirected arenes that thereby provides a general pathway to access a wide range of ß-arylated alcohols, including tetrahydronaphthalen-2-ols and benzopyran-3-ols, with high to excellent chemo- and regioselectivity.

17.
Org Biomol Chem ; 18(13): 2398-2404, 2020 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-32191253

RESUMO

A highly regioselective and enantioselective N-alkylation of isoxazol-5-ones with para-quinone methides promoted by bi-functional squaramide catalysts was developed. This unexpected asymmetric N-addition of isoxazolinones afforded a series of enantioenriched N-diarylmethane substituted isoxazolinones with high yields and enantioselectivities (up to 97 : 3 er). This reaction not only provides a useful approach for intermolecular chiral C-N bond formation but also demonstrates the immense potential of isoxazol-5-ones as N-nucleophiles in catalytic asymmetric reactions.

18.
Chem Commun (Camb) ; 55(96): 14458-14461, 2019 Nov 28.
Artigo em Inglês | MEDLINE | ID: mdl-31728469

RESUMO

A detailed mechanism study on the anion ligand promoted selective C-H bond fluorination is reported. The role of the anion ligand has been clarified by experimental evidence and DFT calculations. Moreover, the nitrate promoted C-F bond reductive elimination enabled a selective C-H bond fluorination of various symmetric and asymmetric azobenzenes to access diverse o-fluoroanilines.

19.
Chem Commun (Camb) ; 55(49): 7049-7052, 2019 Jun 13.
Artigo em Inglês | MEDLINE | ID: mdl-31143893

RESUMO

A palladium catalyzed selective C(sp3)-H arylation and acetoxylation of alcohols using a practical bidentate auxiliary were developed. Masked alcohols were selectively arylated at the ß-position with diverse aryl iodides for the first time. Moreover, an efficient and site-selective acetoxylation of various primary methyl, methylene, and benzylic C(sp3)-H bonds was performed by using cheap K2S2O8 as the external oxidant.

20.
Chem Commun (Camb) ; 55(14): 2019-2022, 2019 Feb 12.
Artigo em Inglês | MEDLINE | ID: mdl-30564815

RESUMO

A novel palladium catalyzed highly para-selective C-H difluoromethylation of electron-deficient aromatic carbonyls was developed. Diverse substituted aromatic ketones and benzoates were selectively difluoromethylated at the remote para-site of carbonyl groups in moderate to good yields. Moreover, the difuoromethylation was also compatible with several complex bioactive molecules.

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